OF THE ASBESTINE EARTH. 185 



powder, which proved to be the fpatbcum pon- 

 der of um. 



The evaporation being carried Aill further, 

 12 of vitriolatcd lime were obtained, of which 

 6.9 were aerated chalk. 



By means of the phlogiflic alkali, 7 of Pruf- 

 fian blue were precipitated, which anfwcrs to 

 nearly 1.2 of calcined iron. 



From the liquor yet remaining, the fixed al- 

 kaii produced 18.6 of aerated magnolia. It 

 ought to well obferved, that the water poured 

 oil* from the precipitate Ihouldboil near an hour, 

 as it always holds a portion of magncfia, and 

 fomctimcs of lime diilblvcd in the aerial acid. 

 This volatile incnftruum being diflipated, the 

 neratcd lime falls almoft immediately, but the 

 fcparation of the magncfia is flow, and not com- 

 pleted until the whole is evaporated to dry- 

 nefs. The fcdiment, containing magnefia a- 

 lone, difiolvcd in the vitriolic acid, being in- 

 fpiflatcd, and afterwards ignited for a quarter of 

 an hour, is Aill wholly foluble in water; what- 

 ever alum may be in it remains burnt and de- 

 prived of its excels of acid ; if gypfum, that 

 ulfo remains; \inlefs wafhcd away by a large 

 quantity t/f water. To dilcover the argillaceous 

 earth, the aerated magncfia, as ilfewhcre ex- 

 plained, is mail fuccefsfully employed as a pre- 

 cipitant of the folution already deprived of its 



iron. 



